Safety Boot Ratings Explained: SB, S1P, S3, S5 and the New Codes
What the codes on a safety boot mean under EN ISO 20345, including the 2022 markings like S3S and S7, so you can match the boot to the job.
Safety footwear sold in the UK and Europe is tested to EN ISO 20345. Every safety boot has a 200 joule toe cap; the code after it tells you what else the boot protects against. The standard was updated in 2022, so you will see both the older codes and the new ones on boots for a while, because a certificate stays valid until it expires.
The main codes
SB. The basic safety boot: toe protection and the core requirements of the standard, nothing more.
S1. SB plus a closed heel area, anti-static properties and energy absorption in the heel. A common choice for dry indoor work such as warehouses.
S1P. S1 plus a penetration-resistant midsole, so a nail or sharp object underfoot cannot come up through the sole.
S2. S1 plus resistance to water getting in and being absorbed by the upper.
S3. S2 plus a penetration-resistant midsole and a cleated (deep-tread) outsole. The everyday choice for construction sites and outdoor work.
S4 and S5. Fully moulded rubber or polymer footwear such as safety wellingtons. S4 is leakproof with the core features; S5 adds a penetration-resistant midsole and cleated outsole.
S6 and S7. New in 2022. S6 is S2 with the whole boot water resistant, and S7 is S3 with the whole boot water resistant.
What the extra letters mean
Since 2022 the type of penetration-resistant midsole is shown in the code. A plain P is a metal insert. PL and PS are non-metallic inserts: PL is tested with the standard 4.5mm nail, PS with a finer 3mm nail. So S3S or S1PS is an S3 or S1P boot with a PS insert, and S3L has a PL insert.
Other markings you may see: SR (slip tested on ceramic tile with glycerine, from the 2022 standard), SRA, SRB and SRC (the older slip markings), HRO (heat-resistant outsole), CI (cold insulation), HI (heat insulation), WR (water-resistant boot), M (metatarsal protection) and FO (fuel oil resistant outsole). ESD boots meet a separate standard for controlling static, for electronics work.
How to choose
Start with the risk assessment for the job. Indoors and dry: S1 or S1P. Outdoors, on site or in the wet: S3, or S7 if feet will be wet all day. Standing water, mud or slurry: S5 wellingtons. If there are nails, screws or glass underfoot, make sure the code includes penetration resistance (S1P, S3, S5, S7).
Every safety boot on our site shows the rating its maker states, and you can filter boots by rating and by UK size. Not sure? Tell us the job and we will suggest a shortlist.
Common questions
What is the difference between S1P and S3 safety boots?
Both have a toe cap and a penetration-resistant midsole. S3 adds water resistance in the upper and a cleated outsole for grip on rough ground, so it suits outdoor and site work. S1P suits dry indoor work.
What does S3S mean on a safety boot?
S3S is an S3 boot, marked under the 2022 version of EN ISO 20345, with a non-metallic penetration-resistant insert tested with a 3mm nail (a PS insert).
Can safety boots be embroidered or printed with a logo?
No. We do not decorate safety footwear. Boots can go on the same order as your branded clothing.